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URL: https://oeis.org/A037066

⇱ A037066 - OEIS

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A037066
a(n)-th prime is the smallest prime containing exactly n 7's.
9
1, 4, 59, 275, 4924, 58623, 506877, 4546755, 30224014, 87818618, 2836649805, 14748299309, 251285857122, 603200604933, 17530836835060, 80446298927642, 2054098188682332, 9577010472498628, 67026825574168206, 1605887402218872982, 16520076587958693329, 156502536697199220470
OFFSET
0,2
LINKS
Andrew R. Booker, The Nth Prime Page.
Kim Walisch, primecount, Fast prime counting function library.
FORMULA
a(n) = A000720(A037067(n)). - Amiram Eldar, Jul 21 2025
MATHEMATICA
(* see A037067 for f *) PrimePi[ Table[ f[n, 7], {n, 1, 12}]]
KEYWORD
nonn,base,hard
AUTHOR
Patrick De Geest, Jan 04 1999
EXTENSIONS
a(0)=1 prepended by Sean A. Irvine, Dec 06 2020
a(14)-a(21) calculated using Kim Walisch's primecount and added by Amiram Eldar, Jul 21 2025
STATUS
approved